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What the hell is the K bayonet


Well-Known Member
Even though I am a Zeiss fan, this is the first time I heard about the K-bayonet. Can anyone tell me what camera has a K-bayonet ?

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OBERKOCHEN/Germany, 19.07.2007.
Carl Zeiss now offers its premium lenses for 35 mm SLR (single lens reflex) cameras for an additional camera connector: the K bayonet. This lens series is sold under the ZK name. Until now, the manually focusable SLR lenses were only available for the F bayonet (ZF) and the M42 screw threads (ZS).

SLR lenses from Carl Zeiss are known for their outstanding image quality and precise, long- lasting mechanical parts.
For the design of its lenses, Carl Zeiss draws on more than 100 years of experience in camera optics and current developments from the production of high-quality lenses for cinematography. Cine lenses from Carl Zeiss have been used in numerous major productions such as The Lord of the Rings and Perfume.

Lenses for the K bayonet will initially be available as Distagon T* 2.8/25 and 2/35, Planar T* 1.4/50 and 1.4/85 as well as Makro-Planar T* 2/50 and 2/100. In the future, the SLR line of lenses will be expanded to offer demanding photographers an even larger selection of focal lengths for their work.

The K bayonet has been available since 1975 and is the standard connector on various well-known analog and digital SLR cameras for the 35 mm format. The manually focused ZEISS SLR lenses (with their transmission elements) for the K bayonet fulfill the SMC-A standard and thus permit the utilization of the shutter priority, aperture priority and programmed auto exposure on all camera models with these features.

With the expansion of the line of SLR lenses, Carl Zeiss provides fans of SLR photography with lenses featuring outstanding imaging performance and high durability with which they can further enhance the performance of their camera system.


The K-mount was Pentax's first bayonet mount, replacing the M42 screw mount, and was introduced in 1976. The first 2 models were the K1000 and the ME. The mount was popular and was adopted by a small number of other camera makers.

I know that K1000's in some guise were still being made as recently as 1997 - there must be millions out there!




Well-Known Member
Hi Joseph,
I can only think that it is the Pentax K mount. If so that is very interesting because CZ lenses could be fitted to the Pentax K10D and the Samsung models.That might put a new complexion on which camera to buy.


Well-Known Member

Just out of interest, before Zeiss hooked up with Yashica, I think I am correct in saying that Zeiss actually had a 'relationship' with Pentax for about a year and one of the fruits of this relationship was the Pentax 'K' bayonet mount....which also explains why it is almost identical to the Contax C/Y mount...

cheers Steve.


Well-Known Member
That's interesting Steve.

Dirk has just posted a message about the new K mount lenses on the Pentax site. I wondered whether C/Y lenses could therefore be altered to Pentax K to fit on Pentax DSLR's.





these are the news:

Zeiss will offer its manual focus range lenses now also for the Pentax K lens mount. No adapter is needed. The Zeiss ZK lenses will work in all modes (A, M, S, P)

The first round will be in August 2007. The last ones (macros) end of this year.

Carl Zeiss SLR lenses - prices

• Planar T* 1,4/50 ZK - € 503,36
• Distagon T* 2,8/25 ZK - € 671,43
• Distagon T* 2/35 ZK - € 671,43
• Planar T* 1,4/85 ZK - € 881,51
• Makro-Planar T* 2/50 ZK - € 881,51
• Makro-Planar T* 2/100 ZK - € 1.343,70

If the k-mount and the C/Y mount are very similar, I could imagine that some clever engineers might be able to develop something. Similar to teh N-lens solution, but without AF. But I would be surprised if Zeiss would do this. They want to sell new stuff. Adapters is nothing with big margins IMHO.

And another point: Lens development is progressing with all brands. Canon, Nikon, Pentax and also Zeiss are making nowadays better lenses than 20 years ago. So the question is, whether it is worth it to invest a lot in any kind of conversion of old lenses.

It might be a better idea to try the new zeiss ZF/ZF/ZS lenses and compare them with the newest development of Canon, Leica, Olympus, Nikon et alii before making any decisions.


Well-Known Member
''So the question is, whether it is worth it to invest a lot in any kind of conversion of old lenses. ''

Apart from conversion of old lenses, one has to consider also whether or not to keep the old ones.

There are many reasons to keep the old ones.

I was thinking about getting the ZF 25 2.8 or now the ZK 25 2.8. However, I have C-Y 28 2, its design is very similar to the new ZF 25 2.8 and they have similar weight. My 28 2 when coupled with my AX can also do close focusing in a similar manner like the new ZF/ZK. So I abandon the idea of getting these new ones.

For 35mm lenses, the star is ZM 35 f2, so I don't need the ZF/ZK35 2.

If one has only C-Y 50 1.4 and C-Y 85 1.4, I would suggest the change to the new ZF/ZK version because they have much better bokeh. I have ZM 50 2 and C-Y 85 1.2, so I don't see the point of getting the new ones.

What about ZF/ZK 50 f2 ? I have C-Y 60 f2.8. I really prefer 60 rather than 50. The old can do down to 1:1 whereas the new one can do 1:2. So I am keeping my old one.

ZF/ZK 100 f2 has breathtaking performance at f2 better than my C-Y 100 f2. My C-Y 100 2.8 can do down to 1:1 whereas ZF can do 1:2. There are important reasons to keep the old macro for scientific and clinical work.

''It might be a better idea to try the new zeiss ZF/ZF/ZS lenses and compare them with the newest development of Canon, Leica, Olympus, Nikon et alii before making any decisions.''

Yes, I agree. Apart from comparing different brands in the same format, I suggest also the comparison with others like Contax 645 and Hasselblad V system and both of them use Zeiss lenses. The difference between different brands of 24X36 are not much. The difference between different formats is a lot.